Many aircraft carry emergency flotation devices should they cease flying while over water. Such flotation devices may include life rafts for passengers and crew, evacuation slides, as well as floats for the aircraft itself. These inflatable structures are deployed by actuation systems in which pressurized fluid is used to initiate rapid deployment of the inflatable structure. In cases where inflatable structures are installed in compartments and remote activation is advantageous or preferable, use of pressurized fluids to convey activation fluid may be employed. Under these circumstances, the mechanical energy transmitted from the control as fluid pressure will typically be converted to linear mechanical motion at the interface of the valve. This is accomplished by a piston of some type located near or adjacent to the inflatable structure's valve. The piston can, in turn, apply tension to the valve's mechanical pull cable to initiate inflation.
One disadvantage to such an arrangement is that care must be taken to prevent independent motion between the piston and valve. Ordinarily, if the valve moves away from the actuator (or vice versa), the inflation may be triggered inadvertently. Furthermore, the piston, which is typically permanently connected to the tubing which acts as a conduit for the pressurized fluid, must often remain attached in some form to the aircraft or primary structure. When the inflatable structure is a life raft that must eventually depart from the compartment but remain connected to its source of inflation fluid, the valve actuator cannot remain with the primary compartment structure.
One solution has been to explore electrical actuators. However, electrical actuators, although generally effective, can create challenges for airlines and/or helicopter operators when maintenance or repairs are needed. Mechanically trained technicians are usually on staff, but electrical trained specialists may not be as prevalent. If an electrical valve actuator needs repair, it can be more expensive and more time-consuming. Accordingly, mechanical valves are generally preferable.
Additionally, prior deployment systems for helicopter floats (which do not detach from the structure) are inoperable in their current form for life rafts, which must detach from the structure. It is thus desirable to develop a way to maintain positioning between the valve and piston, such that the positioning between the components allows detachment when the inflatable structure departs the aircraft. The positioning should be secure, such that aircraft vibrations do not accidentally trigger activation.
In previous attempts, a substantial amount of supporting structure has been required to maintain appropriate positioning of the valve and piston. This results in a rigid mounting structure for the piston and rigid guides that maintain the position of the inflation system valve until the deployment is initiated. Without such support systems, struts, or cradling, the system would potentially detach when not intended. However, the presence of such mounting structures adds expense and complexity to the valve system.
The present inventors have identified a need to improve upon these arrangements. The present disclosure thus provides a valve actuator that completely decouples from the inflatable structure valve. The present disclosure provides this decoupling in a way that eliminates the need for these supporting structures. The present disclosure also provides designs that seek to reduce weight, cost, and bulk of current actuator systems.